[steerablesafe]

Thinkpads are not that easily repairable. Accessing the fan assembly is notoriously cumbersome. For accessing the fan assembly in a T420 you need to remove the keyboard, various PCI cards, the speakers and even the display.

   • “1010 Battery pack” on page 67
   • “1020 ExpressCard blank bezel” on page 68
   • “1050 DIMM slot cover” on page 73
   • “1070 PCI Express Mini Card for wireless WAN” on page 75
   • “1080 Keyboard” on page 77
   • “1110 PCI Express Mini Card for wireless LAN” on page 85
   • “1120 Keyboard bezel assembly, FPC cable, and Bluethooth daughter card” on page 87
   • “1150 Speaker assembly” on page 95
   • “1160 LCD unit” on page 97

https://download.lenovo.com/ibmdl/pub/pc/pccbbs/mobiles_pdf/...

I had many laptops and I can say that the accessing the fan assembly was far easier in non-thinkpad ones. I like to clean the fans by directly accessing them, a gust of compressed air cleaning it is wishful thinking.